Gas piston control system for a firearm

ABSTRACT

A gas system for a firearm having a gas block coupled to a barrel with a gas capture port in communication with a barrel gas port. A sleeve removeably mounted inside the gas block has: a gas conduit; a seat near the gas conduit; a projection; and a rod conduit communicating gas through the projection. A rod movably mounted in the gas block has a cup fitting over the projection. 
     A valve has a knob coupleable to the gas block and a plug moveable within the pressure sleeve with a plunger engageable with the seat to adjust gas flow through the gas conduit to the rod conduit. Gas discharged from a fired cartridge flows against the cup to drive the rod to reload the firearm. The plug is moveable by the knob to a plurality of positions to alter the gas conveyed to the rod.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority of U.S. Provisional Patent ApplicationNo. 61/633,639 filed on Feb. 14, 2012, entitled RIFLE LOWER AND UPPERRECEIVER AND MONOLITHIC HANDGUARD RAIL SYSTEM AND GAS PISTON SYSTEM ANDIMPROVEMENTS, the entire contents of which are hereby incorporatedherein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to firearms and, more particularly, to gasrecoil automatic and semiautomatic firearms and to improvements in thegas systems thereof.

In firearms of the gas operated type in which propellant gases aretapped from the barrel and employed to drive a piston which actuates thegun action, it is often desirable to have some means of regulating theenergy transmitted to the piston. This is especially desirable infirearms that are adapted to fire a variety of types of ammunition, eachdeveloping widely varying pressure characteristics in the barrel.

If no control device is provided to compensate for the varying pressure,the gun must be designed to function with that round of ammunition whichdevelops the least gas pressure energy on the operating piston. However,when firing rounds that develop high pressure levels, excessive energyis transmitted to the action which tends to increase wear and tear andshorten the life of the firearm. Current methods of compensating for thevarying pressure suffer from one or more of the following deficiencies:inability to adjust for a wide range of ammunition, inability to quicklydisassemble and clean the mechanism such as might be necessary in thefield, require the release of light, heat and sound which may render theweapon unsuitable for certain uses and inefficiencies render the methodunsuitable for use with certain types of ammunition, such as subsonicrounds.

Accordingly, an improved system and method of controlling gas pressurein a piston actuated auto-loading firearm is needed.

SUMMARY OF THE INVENTION

An object of the present invention is to integrate an improved gaspiston operating system into a firearm that increases accuracy of thefirearm while retaining an elegant and simple method of operation.Another object of the present invention is to provide an improved gaspiston operating system that is simple to train users to operate.Another object of the present invention is to provide an improved gaspiston operating system that extends the life expectancy of high-wearcomponents. Another object of the present invention is to provide animproved gas piston operating system that has the ability to compensatefor various ammunition types and for the use of various suppressors.

In an embodiment, the present invention is directed to a gas system fora firearm having a barrel with a bore and a gas port in communicationwith the bore. The gas system has a gas block coupled to the barrel, thegas block having a gas capture port in communication with the barrel gasport. A pressure sleeve is removeably mounted inside the gas block, thepressure sleeve having a gas conduit in communication with the gascapture port; a seat proximal to the gas conduit; a projection; and arod conduit for communicating gas through the projection. An operatingrod is movably mounted in the gas block, the operating rod having a cupconfigured to fit over the projection.

A valve is mountable to the gas block, the valve having a knobcoupleable to the gas block; and a plug moveably mountable within thepressure sleeve, the plug having a plunger engageable with the seat toadjust gas flow through the gas conduit to the rod conduit. A spring ismounted around the rod for biasing the rod toward the gas block. Gasdischarged from a fired cartridge flows through the gas port, the gascapture port, the gas conduit and the rod conduit and against the rodcup to drive the rod to reload the firearm. The plug is moveable by theknob to a plurality of positions to alter the gas conveyed to theoperating rod.

The operating rod may have a flange proximal to the cup and gasdischarged from a fired cartridge may also flow against the flange todrive the rod to reload the firearm. The operating rod may also have atleast one gas trap proximal to the flange and gas discharged from afired cartridge may also flow into the gas trap to drive the rod toreload the firearm. The operating rod may have a plurality of gas traps.

In an embodiment, the gas block has a sleeve for holding an end of theoperating rod. The seat and the plunger may be substantially conical.The projection may be substantially cylindrical. In an embodiment, thegas system has a teardown pin, the pressure sleeve has a detent and theteardown pin is mountable in the detent to hold the pressure sleeve inthe gas block. In an embodiment, the knob has a plurality ofcircumferential teeth and the gas block has a spring engageable with theteeth to maintain the position of the knob. Optionally, the knob ismoveable to at least 20 different positions. In an embodiment, the plugfurther comprises at least one groove. The gas system may also have abarrel nut for coupling the barrel to a remainder of the firearm; and aheat sink coupled to the barrel nut, the heat sink having a rod guide.

The present invention according to another embodiment is directed to agas system for a firearm having a barrel with a bore and a gas port incommunication with the bore, the gas system having a gas block coupledto the barrel, the gas block having a gas capture port in communicationwith the barrel gas port. A pressure sleeve is mountable inside the gasblock, the pressure sleeve having: a gas conduit in communication withthe gas capture port and a seat proximal to the gas conduit. Anoperating rod is movably mounted in the gas block over a portion of thepressure sleeve, the operating rod having a cup configured to receivegas from the gas conduit. A needle valve is mountable to the gas block,the valve having a plunger engageable with the seat to adjust gas flowthrough the gas conduit. Gas discharged from a fired cartridge flowsthrough the gas port, the gas capture port and the gas conduit andagainst the cup to drive the operating rod to reload the firearm.

The operating rod may also have a flange proximal to the cup and atleast one gas trap proximal to the flange; and gas discharged from afired cartridge may also flow against the flange and into the gas trapto drive the rod to reload the firearm. The seat and the plunger may besubstantially conical. The gas system may also have a teardown pin andthe pressure sleeve may have a detent; the teardown pin is mountable inthe detent to hold the pressure sleeve in the gas block.

The present invention is also directed to a firearm having a barrel witha bore and a gas port in communication with the bore. The firearm alsohas a gas system having a gas block coupled to the barrel, the gas blockhaving a gas capture port in communication with the barrel gas port. Apressure sleeve is removeably mounted inside the gas block, the pressuresleeve having: a gas conduit in communication with the gas capture port;a seat proximal to the gas conduit; a projection; and a rod conduit forcommunicating gas through the projection. An operating rod is movablymounted in the gas block, the operating rod having a cup configured tofit over the projection; a flange proximal to the cup; and at least onegas trap proximal to the flange.

A valve is mountable to the gas block, the valve having a knob mountableto the gas block; and a plug moveably mountable within the pressuresleeve, the plug having a plunger engageable with the seat to adjust gasflow through the gas conduit to the rod conduit. The firearm also has ameans for biasing the rod toward the gas block. Gas discharged from afired cartridge flows through the gas port, the gas capture port, thegas conduit and the rod conduit and against the rod cup, flange and trapto drive the rod to reload the firearm. The plug is moveable by the knobto a plurality of positions to alter the gas conveyed to the operatingrod. In an embodiment, the seat and the plunger are substantiallyconical. In an embodiment, the gas block also has a means formaintaining position of the knob. In an embodiment, the firearm also hasa barrel nut for coupling the barrel to the firearm and a heat sinkcoupled to the barrel nut, the heat sink having a rod guide.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, aspects and advantages of the present invention willbecome better understood with regard to the following description,appended claims and accompanying figures wherein:

FIG. 1 is a perspective elevation view of a gas system of a firearmaccording to an embodiment of the present invention mounted to a barrel;

FIG. 2 is an exploded view of the gas system of FIG. 1;

FIG. 3 is a side elevation cross sectional view of the gas system ofFIG. 1;

FIGS. 4A and 4B are perspective elevation views of a gas block usable inthe gas system of FIG. 1;

FIG. 5 is a perspective elevation view of a pressure sleeve usable inthe gas system of FIG. 1; and

FIG. 6 is a perspective elevation view of a valve plug usable in the gassystem of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

In the following description of the preferred embodiments, reference ismade to the accompanying drawings which show by way of illustrationspecific embodiments in which the invention may be practiced. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or like parts. It is to be understood thatother embodiments may be utilized and structural and functional changesmay be made without departing from the scope of the present invention.

FIGS. 1 to 6 show a gas piston control system 10 for a firearm accordingto an embodiment of the present invention. The firearm has a cylindricalbarrel 12 having a bore 14. The barrel 12 is mounted to an upperreceiver of the firearm using a barrel nut 18. A heat sink 20 is mountedon the barrel nut 18 at a proximal end of the barrel 12. A chamber inthe upper receiver adjacent the proximal end of the barrel 12 isconfigured to receive a cartridge provided with a projectile. When thecartridge is fired, the projectile exits the barrel 12 at a distal end.

The barrel 12 has a gas port 22 for communicating gas from the bore 14.A gas block 24 is mounted to the barrel 12 proximate to the gas port 22.An operating rod 26 is moveably mounted between the heat sink 20 and thegas block 24.

The gas block 24 has a clamp 28 that fits around the barrel 12. Theclamp 28 has a plurality of mounting holes 30. At least one mountingbolt 32 fits through the mounting holes 30 to tighten the clamp 28 andaffix the gas block 24 to the barrel 12. In an embodiment, there arefour mounting holes 30 and two mounting bolts 32. In an embodiment, themounting bolts 32 are quickly removable to allow for disassembly of thegas block 24 from the barrel 12, such as for cleaning.

As will be understood by those of skill in the art, other means forfastening the gas block onto the barrel may be used. For example, thebarrel may have at least one mounting channel and the clamp may havemounting pins that pass through the mounting holes 30 and through thebarrel mounting channel to affix the gas block 24 to the barrel 12.Additionally, the barrel may have a transverse channel (not shown), thegas block may have a barrel alignment hole 31. A pin 33 may be mountablethrough the barrel alignment hole 31 and the transverse channel on thebarrel to ensure that the gas block is properly positioned on the barrelfor mounting by the clamp.

The components of the gas block 24 will now be considered in more detailwith reference to FIGS. 2 to 6. The gas block 24 has a gas capture port34 which is aligned with the barrel gas port 22 when the gas block 24 ismounted to the barrel 12. The gas capture port 34 allows for gas fromthe bore 14 to be communicated inside the gas block 24. The gas block 24has an operating rod sleeve 36 for holding an end of the operating rod26.

A pressure sleeve 38 is removably positioned in the gas block 24. Thepressure sleeve 38 has a gas conduit 40 that aligns with the gas captureport 34 for communication of gas from the barrel 12. The pressure sleevealso has a rod conduit 42 that passes through a substantiallycylindrically shaped projection 43 for communication of gas to theoperating rod 26. Between the gas conduit 40 and the rod conduit 42 is aseat 44. In an embodiment, the seat 44 is substantially conical.

The pressure sleeve 38 has a lock detent 46 for engagement with ateardown lock 48 on the gas block 24. In an embodiment, the teardownlock 48 has a spring 50 and a pin 52. The spring 50 holds the pin 52 inthe detent 46 until the pin 52 is manually disengaged from the detent 46to allow for removal of the pressure sleeve 38 such as for cleaning.Additionally, the pressure sleeve has an alignment tab 54 engageablewith an alignment detent 56 in the gas block 24 to allow a user toeasily align the pressure sleeve 38 within the gas block 24.

The gas piston control system also has an adjustable valve 58. The valve58 has a knob 60 coupled to a plug 62. The knob 60 threads onto the gasblock 24 to adjustably position the valve plug 62 within the pressuresleeve 38. By turning the valve knob 60, the valve plug 62 is infinitelyadjustable between a position completely blocking the pressure sleevegas conduit 40 and a position completely opening the pressure sleeve gasconduit 40.

With reference to FIG. 6, the valve plug 62 has a shank 64 proximal tothe adjuster valve knob 60, a body 66 and a plunger 68. The plunger 68is configured to correspond to the seat 44 such that the plunger 68 mayform a substantially leak free seal with the seat 44. In an embodiment,the plunger 68 is substantially conically shaped. In an embodiment, thebody 66 further comprises at least one groove 69 to create a sealreducing the amount of gas that can escape around the plug 62.

In an embodiment, an outer circumference of knob 60 has a plurality ofteeth 70. A spring 72 is coupled to the gas block 24 and engages theteeth 70 to limit unintentional rotation of the knob 60 and hold thevalve plug 62 in a given position. The knob 60 contains a plug hole 74through which the shank 64 is fitted. The knob 60 is coupled to theshank 64 using a fastener 76 such as a pin or c-clip. The number ofteeth and the threads may be used to control how many differentpositions the valve plug may have between a fully open and a fullyclosed position. Preferably, the knob may be moved to at least 10different positions, even more preferably to at least 20 differentpositions and even more preferably to at least 40 positions to allow forprecise control over highly variable ammunition and suppressors.

The operating rod 26 will now be considered in more detail withreference to FIGS. 2 and 3. A first end of the operating rod 26 ispositioned in the operating rod sleeve 36 of the gas block 24. Proximalto the first end of the operating rod 26 is a cup 80 for receiving gas.The cup 80 fits over the projection 43 of the pressure sleeve 38. Theoperating rod also has a flange 82 and at least one gas trap 84. The cup80, flange 82 and gas trap 84 allows for a very efficient three stagesystem for activating the operating rod 26 using gas from the bore 14.Gas is initially fired into the cup 80. Gas is then incident on flange82 while the operating rod 26 is fitted in pressure sleeve 38. Finally,pressure from gas leaving the pressure sleeve 38 is picked up the atleast one gas trap 84. The operating rod 26 also has a flange 86 formounting a spring as discussed below.

A second end of the operating rod 26 is positioned in an operating rodguide 88 on the heat sink 20. The operating rod guide 88 helps keep theoperating rod 26 properly aligned. A spring 90 is mounted between theheat sink 20 and the flange 86. The spring 90 provides force on theoperating rod 26 to maintain a secure fit against the pressure sleeve38. The operating rod 26 is actuated by the force of expanding gasfollowing the projectile through the barrel 12. The gas travels throughthe barrel gas port 22, the gas block gas capture port 34 and thepressure sleeve gas conduit 40 and the pressure sleeve rod conduit 42.The gas then acts on the cup 80, flange 82 and gas trap 84 of theoperating rod 26 to turn pneumatic force into mechanical force and pushthe operating rod toward the upper receiver. The operating rod 26 drivesa carrier in the upper receiver to cause a spent cartridge to be ejectedand a new cartridge to be chambered. After the operating rod 26 strikesthe carrier, the spring 90 forces the operating rod 26 back against thepressure sleeve 38.

The barrel nut 18 and heat sink 20 attach the barrel to the upperreceiver of the rifle system, are a rigid attachment point for a handguard and align the operating rod 26 through the upper receiver.Preferably, the barrel nut 18 and heat sink 20 are made from a highlyconductive material to transfer heat from the barrel 12 into the handguard to allow for faster cooling of the barrel 12. In an embodiment, atleast one of the barrel nut 20 and the heat sink 20 are made ofaluminum.

The system of the present invention provides increased consistencybecause the time the driving gas is in the system is reduced, whichlimits the time and area in which the gas can condense. This makes useof the pneumatic gas energy faster, thereby allowing for a shorter cycletime. Additionally, a substantially conically shaped seat 44 and plug 62allows a large surface to be exposed to the hot gases which reduces thewear on the seat 44 and the plug 62. Gas pressure is regulated byrotating the knob 60 to move the plug 62 and the plunger 68 in relationto the seat 44 to progressively open or close the pressure sleeve gasconduit 40. This allows for adjustment of gas pressure to controlcarrier speed for different types of ammunition, as well as forsuppressed fire or different rates of automatic fire.

The gas system according to embodiments of the present invention isintended to be used with firearms having a barrel with a bore and a gasport communicating gas from the bore, such as for example an AR-15 orM16 rifle. Preferably, the upper receiver is designed with a heaviermass than typical upper receivers to compensate for the increased forceand torque involved with the gas piston system. The extra mass alsoallows for more consistent thermal behaviors, including the ability toabsorb more heat out of the gas piston system.

The system of the present invention is designed to direct gas directlyfrom the barrel onto the rod. This system is much more efficient thansystems that require a chamber in a gas block to become pressurized andallows for the use of more varied ammunition. A firearm utilizing thegas system of the present invention may be used in a fully automaticmode with subsonic ammunition and with noise suppression, such as foruse in tactical situations where noise suppression is critical.

The pressure sleeve 38 and operating rod 26 may be easily removed forcleaning, modification or replacement. The valve plug 62 may be removedfrom the gas block 24 by unscrewing the knob 60 until the knob threadsdisengage from threads on the gas block. The valve plug 62 may then bepulled out of the pressure sleeve 38 and the gas block 24. Once thevalve plug 62 has been removed, the pressure sleeve 38 may be removed bymanually disengaging the pin 52 from the detent 46 in the pressuresleeve. Once the pressure sleeve 38 has been removed the operating rod26 may be removed by sliding the operating rod out through the gas block24. This entire operation may be done very quickly and without tools,such as by a soldier in the field.

There is disclosed in the above description and the drawings, a gassystem for a firearm which fully and effectively overcomes thedisadvantages associated with the prior art. However, it will beapparent that variations and modifications of the disclosed embodimentsmay be made without departing from the principles of the invention. Thepresentation of the preferred embodiments herein is offered by way ofexample only and not limitation, with a true scope and spirit of theinvention being indicated by the following claims.

Any element in a claim that does not explicitly state “means” forperforming a specified function or “step” for performing a specifiedfunction, should not be interpreted as a “means” or “step” clause asspecified in 35 U.S.C. §112.

What is claimed is:
 1. A gas system for a firearm having a barrel with abore and a gas port in communication with the bore, the gas systemcomprising: a gas block coupled to the barrel, the gas block comprising:a gas capture port in communication with the barrel gas port; a pressuresleeve removeably mounted inside the gas block, the pressure sleevecomprising: a gas conduit in communication with the gas capture port; aseat proximal to the gas conduit; a projection; and a rod conduit forcommunicating gas through the projection; an operating rod movablymounted in the gas block, the operating rod comprising a cup configuredto fit over the projection; a valve mountable to the gas block, thevalve comprising: a knob coupleable to the gas block; and a plugmoveably mountable within the pressure sleeve, the plug having a plungerengageable with the seat to adjust gas flow through the gas conduit tothe rod conduit; and a spring mounted around the rod for biasing the rodtoward the gas block; wherein gas discharged from a fired cartridgeflows through the gas port, the gas capture port, the gas conduit andthe rod conduit and against the rod cup to drive the rod to reload thefirearm; and the plug is moveable by the knob to a plurality ofpositions to alter the gas conveyed to the operating rod.
 2. The gassystem of claim 1 wherein the operating rod further comprises a flangeproximal to the cup and wherein gas discharged from a fired cartridgefurther flows against the flange to drive the rod to reload the firearm.3. The gas system of claim 2 wherein the operating rod further comprisesat least one gas trap proximal to the flange and wherein gas dischargedfrom a fired cartridge further flows into the gas trap to drive the rodto reload the firearm.
 4. The gas system of claim 3 wherein theoperating rod further comprises a plurality of gas traps.
 5. The gassystem of claim 1 wherein the gas block further comprises a sleeve forholding an end of the operating rod.
 6. The gas system of claim 1wherein the seat and the plunger are substantially conical.
 7. The gassystem of claim 1 wherein the projection is substantially cylindrical.8. The gas system of claim 1 further comprising a teardown pin; andwherein the pressure sleeve further comprises a detent; and the teardownpin is mountable in the detent to hold the pressure sleeve in the gasblock.
 9. The gas system of claim 1 wherein the knob has a plurality ofcircumferential teeth and the gas block has a spring engageable with theteeth to maintain the position of the knob.
 10. The gas system of claim10 wherein the knob is moveable to at least 20 different positions. 11.The gas system of claim 1 wherein the plug further comprises at leastone groove.
 12. The gas system of claim 1 further comprising: a barrelnut for coupling the barrel to a remainder of the firearm; and a heatsink coupled to the barrel nut, the heat sink having a rod guide.
 13. Agas system for a firearm having a barrel with a bore and a gas port incommunication with the bore, the gas system comprising: a gas blockcoupled to the barrel, the gas block comprising: a gas capture port incommunication with the barrel gas port; a pressure sleeve mountableinside the gas block, the pressure sleeve comprising: a gas conduit incommunication with the gas capture port; and a seat proximal to the gasconduit; an operating rod movably mountable in the gas block over aportion of the pressure sleeve, the operating rod comprising a cupconfigured to receive gas from the gas conduit; and a needle valvemountable to the gas block, the valve comprising a plunger engageablewith the seat to adjust gas flow through the gas conduit; wherein gasdischarged from a fired cartridge flows through the gas port, the gascapture port and the gas conduit and against the cup to drive theoperating rod to reload the firearm.
 14. The gas system of claim 13wherein the operating rod further comprises a flange proximal to the cupand at least one gas trap proximal to the flange; and wherein gasdischarged from a fired cartridge further flows against the flange andinto the gas trap to drive the rod to reload the firearm.
 15. The gassystem of claim 14 wherein the seat and the plunger are substantiallyconical.
 16. The gas system of claim 13 further comprising a teardownpin; and wherein the pressure sleeve further comprises a detent; and theteardown pin is mountable in the detent to hold the pressure sleeve inthe gas block.
 17. A firearm comprising: a barrel comprising a bore anda gas port in communication with the bore a gas system comprising: a gasblock coupled to the barrel, the gas block comprising: a gas captureport in communication with the barrel gas port; a pressure sleeveremoveably mounted inside the gas block, the pressure sleeve comprising:a gas conduit in communication with the gas capture port; a seatproximal to the gas conduit; a projection; and a rod conduit forcommunicating gas through the projection; an operating rod movablymounted in the gas block, the operating rod comprising: a cup configuredto fit over the projection; a flange proximal to the cup; and at leastone gas trap proximal to the flange; a valve mountable to the gas block,the valve comprising: a knob mountable to the gas block; and a plugmoveably mountable within the pressure sleeve, the plug having a plungerengageable with the seat to adjust gas flow through the gas conduit tothe rod conduit; and a means for biasing the rod toward the gas block;wherein gas discharged from a fired cartridge flows through the gasport, the gas capture port, the gas conduit and the rod conduit andagainst the rod cup, flange and trap to drive the rod to reload thefirearm; and the plug is moveable by the knob to a plurality ofpositions to alter the gas conveyed to the operating rod.
 18. The gassystem of claim 17 wherein the seat and the plunger are substantiallyconical.
 19. The gas system of claim 18 further comprising a means formaintaining position of the knob.
 20. The gas system of claim 19 furthercomprising: a barrel nut for coupling the barrel to the firearm; a heatsink coupled to the barrel nut, the heat sink having a rod guide.